Generally, an electric appliance used in a residential house or in an office building is connected to a power supply receptacle via a plug. When the electric appliance is not in use, a user would usually directly turn a power switch on the electric appliance to off. However, according to the design of an electric appliance, even when the power switch thereof is turned to off, the electric appliance is still in a standby state, and some electronic elements in the electric appliance will still consume electric power.
In the residential houses or the office buildings, including the public spaces, the accumulated power consumed and wasted by the internal electronic elements in the turned-off electric appliances is surprisingly high. And, serious waste of electric energy also occurs due to people's negligence in leaving electric appliances in the on state when the electric appliances should be turned off.
Generally, a power receptacle or a receptacle provided on an extension cord is designed for a plug on a power cord to plug in. When a consumer uses an electric appliance and wants to set a time for the electric appliance to automatically turn on or turn off at the set time point, the consumer has to buy an additional timer and connects the timer to the receptacle, so that the receptacle has the timing function. Then, the consumer can connect the power cord of the electric appliance to the timer. In this way, the power receptacle can have increased function and applicability to benefit general family and industrial users. However, the additional timer will increase the consumer's cost and bring inconveniences to the consumer.
In a conventional power control and management technique implement as a wireless power control and management device, there are included multiple arrayed slave sets and a master set. Each of the slave sets is provided with a high-frequency receiver circuit, a CPU control circuit, and a radio module. The CPU control unit is connected to switch and receptacle power supply circuits. The master set is provided with a high-frequency receiver circuit, a CPU control circuit, a radio module, a plurality of keys, and a display circuit.
Two-way signal transmission and reception is allowed between the master set and each of the slave sets, and each of the keys on the master set corresponds to a specific slave set. The CPU control circuit on the master set orders the radio module thereof to transmit a signal to a correspondent slave set, and the transmitted signal is received and further transmitted by the high-frequency receiver circuit of the slave set to the CPU control circuit of the slave set for controlling the switch and receptacle power supply circuits connected to that slave set to match the on/off state of the corresponding key on the master set.
In the above-described patented wireless power control and management device, the master-slave relation between the master set and each of the slave sets is centrally controlled. A slave set having been set to off by the master set is not allowed to be turned on from the end of the slave set. Thus, in the event lamps in a certain office are turned off by a master set, persons in the office can do nothing but to dangerously move in the dark. Further, the master set of such centrally controlled power control and management device is subject to purposeful and vicious destruction and invasion. In such a case, electric appliances connected to the slave sets will become failed to cause inconveniences to the users.
In another conventional power control and management technique implemented as an extension cord receptacle with timing function, a housing of which is provided with at least one flush plug receptacle connected to a timer circuit inside the housing. The timer circuit controls the timing setting of a corresponding receptacle. An extension cord and a plug are connected to the housing. A character liquid crystal display (LCD) is provided on the housing, and a plurality of keys are provided to one side of the character LCD. The character LCD and the keys are electrically connected to the timer circuits. A timing point for the timer circuit can be set via the keys. When an electric appliance is connected to one of the receptacles, the timer circuit will start counting until the timing point set for the receptacle is reached, and then the timer circuit will control the corresponding receptacle to on or off, so as to turn on or turn off the electric appliance connected to the receptacle.
Generally, the extension cord receptacle is disadvantageously laid on a floor near a corner and is not easily accessible for manually setting the timing point. Further, when the timer circuit controls the corresponding receptacle to on or off, the setting by the timer circuit can not be released from outside of the receptacle. In the event the extension cord with the receptacles thereof preset to ON is connected to a power source, dangers tend to occur due to a sudden conduction of the extension cord. On the other hand, in the event the extension cord with the receptacles thereof preset to OFF is connected to a power source and does not work, it tends to cause a wrong determination that the electric appliance is failed.
It is therefore tried by the inventor to develop a novel extension cord with wireless timing function to eliminate the drawbacks in the prior art.